We are having an issue with one install where occassionally recipes being sent to a PLC from Ignition ‘hang’, meaning when the customer presses the ‘Send To PLC’ button, nothing reaches the PLC. Usually a Gateway reboot resolves the issue.
There is a lot going on behind the scene when the ‘Send To PLC’ button is pressed. Database queries are invloved ensuring proper inventory in bins, using older incredients first etc… before the actual recipe is sent to the PLC.
The programmer I have working on this project refuses to acknowledge that his code may have something wrong. He insists its is network or windows issues causing problems.
I have taken it upon myself to review the code and get advanced training in order to get this problem resolved.
One thing I have noticed, which I think may be an issue ,is the the use of a PLC Boolean Tag being used as a one shot trigger. In the scripting of the pushbutton, one line of code sets the PLC Tag to 1. This Tag is then used elsewhere in code.
In the final transaction group that sends data to the PLC this one shot Tag is set to 0.
I think it would be better practice to use a DB Tag as a one shot than a realworld PLC tag.
Am I correct in this assumption?